Lone Offender: A Study of Lone Offender Terrorism in the United States (1972--2015) [open pdf - 2MB]
From the Introduction: "Operationally defining the lone offender terrorist is challenging, as the nature of terrorism is both highly political and contextually dependent. Over the years, there has been disagreement over the classification of violent acts under the label of 'terrorism.' While an argument can be made that the infliction of fear upon a targeted group or the public is sufficient to classify an act as terrorism, the FBI definition of terrorism requires a purported motivation that goes beyond exclusively personal motivations and attempts to influence change in furtherance of extremist ideologies of a social, political, religious, racial or environmental nature. The focus of the current study examined offenders who carried out their attacks independent of any direction from a terrorist group or organization."
Federal Bureau of Investigation: https://www.fbi.gov/